Fuel system using redox flow battery

ABSTRACT

An automotive or other power system including a flow cell, in which the stack that provides power is readily isolated from the storage vessels holding the cathode slurry and anode slurry (alternatively called “fuel”) is described. A method of use is also provided, in which the “fuel” tanks are removable and are separately charged in a charging station, and the charged fuel, plus tanks, are placed back in the vehicle or other power system, allowing fast refueling. The technology also provides a charging system in which discharged fuel is charged. The charged fuel can be placed into storage tanks at the power source or returned to the vehicle. In some embodiments, the charged fuel in the storage tanks can be used at a later date. The charged fuel can be transported or stored for use in a different place or time.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/306,610, filed Jun. 17, 2014, which is a continuation of U.S. patentapplication Ser. No. 12/755,379, filed Apr. 6, 2010, now U.S. Pat. No.8,778,552, entitled “Fuel System Using Redox Flow Battery,” which claimspriority to and the benefit of U.S. Provisional Application No.61/235,859, filed on Aug. 21, 2009, entitled “Fuel System Using RedoxFlow Battery,” and U.S. Provisional Application No. 61/166,958, filed onApr. 6, 2009, entitled “Fuel System Using Redox Flow Battery,” thedisclosures of which are hereby incorporated by reference in theirentirety.

INCORPORATION BY REFERENCE

All patents, patent applications and publications cited herein arehereby incorporated by reference in their entirety in order to morefully describe the state of the art as known to those skilled therein asof the date of the invention described herein.

BACKGROUND

Redox flow batteries, also known as a flow cells or redox batteries orreversible fuel cells, are energy storage devices in which the positiveand negative electrode reactants are soluble metal ions in liquidsolution that are oxidized or reduced during the operation of the cell.Using two soluble redox couples, one at the positive electrode and oneat the negative electrode, solid-state reactions are avoided. A redoxflow cell typically has a power-generating assembly comprising at leastan ionically transporting membrane separating the positive and negativeelectrode reactants (also called cathode slurry and anode slurry,respectively), and positive and negative current collectors (also calledelectrodes) which facilitate the transfer of electrons to the externalcircuit but do not participate in the redox reaction (i.e., the currentcollector materials themselves do not undergo Faradaic activity).

Differences in terminology for the components of a flow battery andthose of conventional primary or secondary batteries are herein noted.The electrode-active solutions in a flow battery are typically referredto as electrolytes, and specifically as the cathode slurry and anodeslurry, in contrast to the practice in lithium ion batteries where theelectrolyte is solely the ion transport medium and does not undergoFaradaic activity. In a flow battery the non-electrochemically activecomponents at which the redox reactions take place and electrons aretransported to or from the external circuit are known as electrodes,whereas in a conventional primary or secondary battery they are known ascurrent collectors.

While redox flow batteries have many attractive features, including thefact that they can be built to almost any value of total charge capacityby increasing the size of the cathode slurry and anode slurryreservoirs, one of their limitations is that their energy density, beingin large part determined by the solubility of the metal ion redoxcouples in liquid solvents, is relatively low. The extent to which metalion solubilities may be increased is limited.

In the field of aqueous electrolyte batteries, and specificallybatteries that utilize zinc as an electroactive material, electrolytesthat comprise a suspension of metal particles and in which thesuspension is flowed past the membrane and current collector, have beendescribed. See for example U.S. Pat. Nos. 4,126,733 and 5,368,952 andEuropean Patent EP 0330290B1. The stated purpose of such electrodes isto prevent detrimental Zn metal dendrite formation, to preventdetrimental passivation of the electrodes, or to increase the amount ofzincate that can be dissolved in the positive electrode as the celldischarges. However, the energy density of such aqueous batteries evenwhen electrolytes with a suspension of particles are used remainsrelatively low. Such batteries cannot provide a high enough specificenergy to permit practical operation of an electric vehicle, nor do theyprovide a substantial improvement in specific energy or energy densityover conventional redox batteries for stationary energy storage,including for example applications in grid services or storage ofintermittent renewable energy sources such as wind and solar power.

SUMMARY

Swappable fuel tank for fueled vehicles using flow cells is described.The swappable fuel tank includes a cathode slurry and/or an anode slurrythat can be used in a redox flow battery to generate power. As describedin greater detail below, the anode and cathode slurries flow past an ionpermeable membrane and electrodes connected to an external circuit andthereby engage in redox chemistry. The swappable fuel tanks and the flowbattery cells (in combination referred to as a “stack”) are referred to,in combination, as the ‘power system.’ The fuel tank is configured to beeasily removed from the power system and easily emptied and refilled.Thus, spent fuel can be replaced and/or the quality or properties can bevaried from filling to filling to provide greater versatility orfunctionality to the power system.

In other embodiments, the power system is equipped with internalmonitoring capability so that the state of the battery is known. Powersystem attributes that may be monitored can provide information of thestate of charge of the anode and cathode slurries, i.e., whether thetank ‘full’ or ‘empty’. The monitoring system can also provideinformation regarding other properties of the system to generallyprovide information about the state of health of the power system andidentify conditions that can be dangerous or require correction.

In another aspect, the power system can include an electrical energystorage device and power source that is simultaneously a conventionalrechargeable battery and a flow cell in one integrated device. It isapplicable to various battery chemistries, including aqueous batteriessuch as nickel metal hydride types, and nonaqueous batteries includinglithium rechargeable batteries, sodium rechargeable batteries, orbatteries based on other alkali or alkaline earth or non-alkalineworking ions. Considering one embodiment based on lithium ion chemistry,the basic construction of such a cell has a separator, on one side ofwhich is a lithium battery positive electrode or a negative electrode,or both, as in a conventional rechargeable lithium battery. That is,said electrodes comprise cathode or anode active material, and maycomprise a coating of the active material on a metallic currentcollector, or may be a stand-alone electrode layer such as a densifiedor sintered layer comprising the active material, optionally with otherconstituents such as polymer binders or carbonaceous conductiveadditives or metallic additives or binders. These ion-storage electrodeswill be referred to as the stationary electrodes. However, unlike aconventional lithium battery electrode, one or both of said stationaryelectrodes is permeable to a flow cell cathode slurry or anode slurry,so that during operation of the device, it is possible to charge ordischarge only the active materials on the stationary electrode, onlythe flow cell cathode slurry or anode slurry, or both.

In one or more embodiments, the redox flow batteries have a multi-cellstack design including semi-solid or condensed liquid reactant in anodeslurry or cathode slurry. In some embodiments, the redox flow batteriesare connected to anode slurry and cathode slurry storage tanks throughflow valves and pumps. In some embodiments, the direction of the flow ofthe anode slurry/cathode slurry can be reversed depending on thecharge/discharge stages of the anode slurry/cathode slurry. In somespecific embodiments, the storage tank include a bladder which storesthe discharged semi-solid or condensed liquid reactant the dischargedmaterial can be transferred back into the device for charging. In someembodiments, the semi-solid or condensed liquid reactant is introducedinto each cell compartment of the stacked cell through a manifold. Insome embodiments, valves can be installed on the manifold. In someembodiments, the valve can be positioned just before the inlet of thecell compartment. In some embodiments, the valve can be positioned justafter the outlet of the cell compartment. The valves can reduced therisk of short-circuit of the system.

In some embodiments, one or more injectors are connected to the manifoldof the semi-solid multi-stack cell and pressurized regions (plenum) areformed within the manifold. The plenum can be used to deliver cathodeslurry or anode slurry into a single cell compartment or a group of cellcompartments.

In some embodiments, the semi-solid or condensed liquid redox flowmulti-cell stack can be assembled by stacked plates. The manifolds ofthe redox flow multi-cell stack are formed by stacking plates together.In some specific embodiments, the inside surfaces of the manifold can becoated with non-electrically-conducting material to minimize shuntcurrent across liquid.

In one aspect, a method of operating a portable device including a powersystem housed within the device is described, including:

-   -   providing a plurality of flow cells, each flow cell comprising:        -   a positive electrode current collector,        -   a negative electrode current collector,        -   an ion-permeable membrane separating the positive and            negative current collectors;        -   wherein the positive electrode current collector and the            ion-permeable membrane define a positive electroactive zone            for accommodating a positive electroactive material;        -   wherein the negative electrode current collector and the            ion-permeable membrane define a negative electroactive zone            for accommodating a negative electroactive material; wherein            at least one of the positive and negative electroactive            materials comprises a flowable redox composition in the            electroactive zone;        -   at least one dispensing vessel for dispensing a flowable            redox composition into one of the positive or negative            electroactive zone; wherein the dispensing vessel is            connected with the plurality of flow cells and in fluidic            communication with the electroactive zone and the dispensing            vessel is capable of being connected and disconnected from            the flow cell; and        -   at least one receiving vessel for receiving flowable redox            composition from one of the positive or negative            electroactive zone, wherein the receiving vessel is            connected with the flow cell and in fluidic communication            with said electroactive zone and the receiving vessel is            capable of being connected and disconnected from the flow            cell;    -   introducing the flowable redox composition from the dispensing        vessel into at least one of the electroactive zones to cause the        flow cell to discharge to provide electric energy to operate the        device; and    -   receiving the discharged redox composition in the receiving        vessel.

In any preceding embodiment, the method further includes refueling thepower system by replacing the dispensing vessel with a new dispensingvessel containing fresh flowable redox composition.

In any preceding embodiment, the method further includes replacing thereceiving vessel with a new empty receiving vessel.

In any preceding embodiment, the portable device is a vehicle.

In any preceding embodiment, the portable device is a portable powergenerator.

In any preceding embodiment, the vehicle is a land, air, or watervehicle.

In any preceding embodiment, the redox composition comprises a flowablesemi-solid or condensed liquid ion-storing redox composition capable oftaking up and releasing the ions during operation of the cell.

In any preceding embodiment, the method further includes refueling thepower system by replacing the dispensing vessel containing the redoxcomposition with a new dispensing vessel containing a fresh flowableredox composition.

In any preceding embodiment, the fresh redox composition has at leastone different characteristic from the redox composition.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different power densities.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different energy densities.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different semi-solid particle sizes.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different electroactive material concentrations.

In any preceding embodiment, the fresh redox composition has smallersemi-solid particle size and higher power density than the redoxcomposition.

In any preceding embodiment, the fresh redox composition has higherelectroactive material concentration and higher energy density than theredox composition.

In any preceding embodiment, the dispensing vessel and receiving vesselform a unitary body.

In any preceding embodiment, the plurality of flow cells form a stack offlow cells, and the dispensing and receiving vessels are reversiblyconnected with the flow cell stack.

In any preceding embodiment, the flow cells are connected in parallel.

In any preceding embodiment, the flow cells are connected in series.

In any preceding embodiment, the method further includes providingcomprising a pump disposed between one or both of the dispensing andreceiving vessels and the flow cell stack.

In any preceding embodiment, the pump is a reversible flow pump that isoperable for flow in both directions.

In any preceding embodiment, the dispensing or receiving vesselscomprise a flexible bladder.

In any preceding embodiment, the method further includes valvespositioned at the entrance of each fuel cell to control the flow ofredox composition into the respective flow cell and minimize shuntcurrent between adjacent flow cells.

In any preceding embodiment, the method further includes providing amultiport injection system configured and arranged to control the amountof redox composition delivered to each electroactive zone of each flowcell.

In any preceding embodiment, the multiport injection system comprises aplurality of compartments, each compartment in flow communication with asubset of the flow cells in the flow cell stack and injectors forintroducing redox composition into each compartment.

In any preceding embodiment, the pressure in the plurality ofcompartment is greater than the pressure in the electroactive zonepressure.

In any preceding embodiment, the method further includes comprising acooling system for circulating a coolant in the flow cell stack.

In any preceding embodiment, the method further includes providing amonitoring meter connected to one or both of the dispensing andreceiving vessels for monitoring the volume or content of the redoxcomposition in one or both of the dispensing or receiving vessel.

In any preceding embodiment, the method further includes replenishingthe dispensing vessel with fresh redox composition.

In any preceding embodiment, replenishing the dispensing vesselcomprises introducing new redox composition into the dispensing vessel.

In any preceding embodiment, the method further includes removing thedischarged redox composition from the receiving vessel.

In any preceding embodiment, removing the discharged redox compositionfrom the receiving vessel comprises emptying the receiving vessel ofdischarged redox composition.

In any preceding embodiment, the dispensing and receiving vessel form aunitary body, the unitary body having a movable membrane between thereceiving and dispensing compartments and the method further comprisedreplacing the unitary body with a new unitary body comprising a powerstorage vessel containing fresh flowable semi-solid or condensed liquidion-storing redox compositions and an empty spent redox compositionstorage vessel.

In any preceding embodiment, the method further includes monitoring thelevels of the flowable redox compositions in the dispensing or receivingvessels.

In any preceding embodiment, the method further includes

-   -   reversing the direction of flow of the redox composition so that        the spent redox composition flows from the receiving vessel to        the electroactive zone; and    -   applying a reverse voltage to the power system to recharge the        discharged redox composition.

In any preceding embodiment, the method further includes advancing therecharged redox composition from the electroactive zone to thedispensing vessel for storage.

In any preceding embodiment, the flow of the spent redox composition iscontrolled by a reversible pump.

In any preceding embodiment, the particle size of the flowablesemi-solid ion-storing redox composition being discharged is selected toprovide a preselected power density.

In any preceding embodiment, the load in wt percent of the flowablesemi-solid ion-storing redox composition being discharged is selected toprovide a preselected energy capacity of the redox composition.

In any preceding embodiment, the method further includes monitoring thecondition of the redox composition before during or after discharge.

In any preceding embodiment, the condition monitored comprises thetemperature, flow rates, or the relative amounts of the cathode or anoderedox compositions.

In any preceding embodiment, the method further includes modifying aproperty of the redox composition based on the results of themonitoring.

In any preceding embodiment, the method further includes increasing theflow rate of the redox composition along the electroactive zone toincrease the power of the flow cell.

In any preceding embodiment, the method further includes reconditioningthe flowable semi-solid or condensed liquid ion-storing redoxcomposition.

In any preceding embodiment, the reconditioning comprises

-   -   sequesting residual water from the the redox composition;    -   adding additional salt to improve ion conductivity;    -   adding solvents or electrolyte additives;    -   adding additional solid phases including active materials used        for ion storage, or conductive additives;    -   separating solid phases from the liquid electrolyte;    -   adding coagulation aids;    -   replacing the liquid electrolyte; or    -   any combination thereof.

In any preceding embodiment, at least one of the flow cells comprises:

-   -   an electrode comprising a flowable semi-solid or condensed        liquid ion-storing redox composition capable of raking up and        releasing the ions during operation of the cell; and    -   a stationary electrode.

In another aspect, a method of operating a stationary device comprisinga power system housed within the device is described, comprising:

-   -   providing a plurality of flow cells, each flow cell comprising:        -   a positive electrode current collector,        -   a negative electrode current collector,        -   an ion-permeable membrane separating the positive and            negative current collectors;        -   wherein the positive electrode current collector and the            ion-permeable membrane define a positive electroactive zone            for accommodating a positive electroactive material;        -   wherein the negative electrode current collector and the            ion-permeable membrane define a negative electroactive zone            for accommodating a negative electroactive material; wherein            at least one of the positive and negative electroactive            materials comprises a flowable redox composition in the            electroactive zone;    -   at least one dispensing vessel for dispensing a flowable redox        composition into one of the positive or negative electroactive        zone; wherein the dispensing vessel is connected with the        plurality of flow cells and in fluidic communication with the        electroactive zone and the vessel is capable of being connected        and disconnected from the flow cell; and    -   at least one receiving vessel for receiving flowable redox        composition from one of the positive or negative electroactive        zone, wherein die receiving vessel is connected with the flow        cell and in fluidic communication with the electroactive zone        and the vessel is capable of being connected and disconnected        from the flow cell;    -   introducing the flowable redox composition from the dispensing        vessel into at least one of the electroactive zones to cause the        flow cell to discharge to provide electric energy to operate the        device, and    -   receiving the discharged redox composition in the receiving        vessel.

In any preceding embodiment, the method further includes furthercomprising refueling the power system by replacing the dispensing vesselwith a new dispensing vessel containing fresh flowable redoxcomposition.

In any preceding embodiment, the method further includes replacing thereceiving vessel with a new empty receiving vessel.

In any preceding embodiment, the stationary device is a stationary powergenerator.

In any preceding embodiment, the redox composition comprises a flowablesemi-solid or condensed liquid ion-storing redox composition capable oftaking up and releasing the ions during operation of the cell.

In any preceding embodiment, the method further includes refueling thepower system by replacing the dispensing vessel containing the redoxcomposition with a new dispensing vessel containing a fresh flowableredox composition.

In any preceding embodiment, the fresh redox composition has at leastone different characteristics from the redox composition.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different power densities.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different energy densities.

In any preceding embodiment, the plurality of flow cells form a stack offlow cells, and the dispensing and receiving vessels are reversiblyconnected with the flow cell stack.

In any preceding embodiment, the method further includes providing amonitoring meter connected to one or both of the dispensing andreceiving vessels for monitoring the volume or content of the redoxcomposition in one or both of the dispensing or receiving vessel.

In any preceding embodiment, the dispensing and receiving vessel form aunitary body, the unitary body having a movable membrane between thereceiving and dispensing compartments and the method further comprisesreplacing the unitary body with a new unitary body comprising a powerstorage vessel containing fresh flowable semi-solid or condensed liquidion-storing redox compositions and an empty spent redox compositionstorage vessel.

In any preceding embodiment, the method further includes

-   -   reversing the direction of flow of the redox composition so that        the spent redox composition flows from the receiving vessel to        the electroactive zone; and    -   applying a reverse voltage to the power system to recharge the        discharged redox composition.

In yet another aspect, a vehicle comprising a power system housed withinthe vehicle is described, the power system comprising:

-   -   a plurality of flow cells, each flow cell comprising:        -   a positive electrode current collector,        -   a negative electrode current collector,        -   an ion-permeable membrane separating the positive and            negative current collectors;        -   wherein the positive electrode current collector and the            ion-permeable membrane define a positive electroactive zone            for accommodating a positive electroactive material;        -   wherein the negative electrode current collector and the            ion-permeable membrane define a negative electroactive zone            for accommodating a negative electroactive material; wherein            at least one of the positive and negative electroactive            materials comprises a flowable redox composition in the            electroactive zone;    -   at least one dispensing vessel for dispensing a flowable redox        composition into one of the positive or negative electroactive        zone; wherein the dispensing vessel is connected with the        plurality of flow cells and in fluidic communication with the        electroactive zone and the vessel is capable of being connected        and disconnected from the flow cell; and    -   at least one receiving vessel for receiving flowable redox        composition from one of the positive or negative electroactive        zone, wherein the receiving vessel is connected with the flow        cell and in fluidic communication with the electroactive zone        and the vessel is capable of being connected and disconnected        from the flow cell; wherein the dispensing vessel and are        located to provide access for removal and replacing.

In any preceding embodiment, the power system is capable of beingrefueled by replacing the dispensing vessel containing the flowableredox composition with a new dispensing vessel containing fresh flowableredox composition.

In any preceding embodiment, the receiving vessel is capable of beingreplaced with a new empty receiving vessel.

In any preceding embodiment, the redox composition comprises a flowablesemi-solid or condensed liquid ion-storing redox composition capable oftaking up and releasing the ions during operation of the cell.

In any preceding embodiment, the power system is capable of beingrefueled by replacing the dispensing vessel containing the flowableredox composition with a new dispensing vessel containing fresh flowableredox composition.

In any preceding embodiment, the fresh redox composition has at leastone different characteristic from the redox composition.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different power densities.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different energy densities.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different semi-solid particle sizes.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different electroactive material concentrations.

In any preceding embodiment, the dispensing vessel and receiving vesselform a unitary body.

In any preceding embodiment, the plurality of flow cells form a stack offlow cells, and the dispensing and receiving vessels are reversiblyconnected with the flow cell stack.

In any preceding embodiment, the power system further comprising a pumpdisposed between one or both of the dispensing and receiving vessels andthe flow cell stack.

In any preceding embodiment, the pump is a reversible flow pump that isoperable for flow in both directions.

In any preceding embodiment, the dispensing and receiving vesselscomprise a flexible bladder.

In any preceding embodiment, the vehicle further includes valvespositioned at the entrance of each fuel cell to control the flow ofredox composition into the respective flow cell and minimize shuntcurrent between adjacent fuel cells.

In any preceding embodiment, the vehicle further includes a multiportinjection system configured and arranged to control the amount of redoxcomposition delivered to each electroactive zone of each flow cell.

In any preceding embodiment, the vehicle further includes a monitoringmeter connected to one or both of the dispensing and receiving vesselsfor monitoring the volume or content of the redox composition in one orboth of the dispensing or receiving vessel.

In any preceding embodiment, the dispensing and receiving vessel form aunitary body, the unitary body having a movable membrane between thereceiving and dispensing compartments and the method further comprisesreplacing the unitary body with a new unitary body comprising a powerstorage vessel containing fresh flowable semi-solid or condensed liquidion-storing redox compositions and an empty spent redox compositionstorage vessel.

In yet another aspect, a power system comprising, comprising:

-   -   a plurality of flow cells, each flow cell comprising:        -   a positive electrode current collector,        -   a negative electrode current collector,        -   an ion-permeable membrane separating the positive and            negative current collectors;        -   wherein the positive electrode current collector and the            ion-permeable membrane define a positive electroactive zone            for accommodating the positive electrode;        -   wherein the negative electrode current collector and the            ion-permeable membrane define a negative electroactive zone            for accommodating the negative electrode; wherein at least            one of the positive and negative electrode comprises a            flowable semi-solid or condensed liquid ion-storing redox            composition in the electroactive zone which is capable of            taking up and releasing the ions during operation of the            cell;    -   at least one dispensing storage vessel for dispensing the        flowable semi-solid or condensed liquid ion-storing redox        composition into one of the positive or negative electroactive        zone; wherein the dispensing storage vessel is connected with        the plurality of flow cells and in fluidic communication with        the electroactive zone and the dispensing vessel is capable of        being connected and disconnected from the flow cell; and    -   at least one receiving storage vessel for receiving flowable        redox composition from one of the positive or negative        electroactive zone, wherein the receiving vessel is connected        with the flow cell and in fluidic communication with the        electroactive zone and the receiving vessel is capable of being        connected and disconnected from the flow cell.

In any preceding embodiment, the positive electrode comprises a cathodeslurry comprising the flowable semi-solid or condensed liquidion-storing redox compositions and the negative electrode comprises ananode slurry comprising the flowable semi-solid or condensed liquidion-storing redox compositions.

In any preceding embodiment, the power storage vessel and the spentredox composition storage vessel form a unitary body.

In any preceding embodiment, the plurality of flow cells form a stack offlow cells, wherein each flow cell comprises at least one electrodecomprising a flowable semi-solid or condensed liquid ion-storing redoxcomposition which is capable of taking up or releasing the ions duringoperation of the cell; and the dispensing and receiving vessels arereversibly connected with the flow cell stack.

In any preceding embodiment, the flow cells are connected in parallel.

In any preceding embodiment, the flow cells are connected in series.

In any preceding embodiment, the power system further includes a pumpdisposed between one or both of the dispensing and receiving vessels andthe flow cell.

In any preceding embodiment, the pump is a reversible flow pump.

In any preceding embodiment, the dispensing and receiving vesselscomprise a flexible bladder.

In any preceding embodiment, the power system further includes valvespositioned at the entrance of each fuel cell to control the flow ofredox composition into the respective flow cell and minimize shuntcurrent between adjacent fuel cells.

In any preceding embodiment, the power system further includes amultiport injection system configured and arranged to control the amountof redox composition delivered to each electroactive zone of each flowcell.

In any preceding embodiment, the multiport injection system comprisesinjectors for introducing redox composition into a compartment supplyingredox composition to a sub-portion of the total flow cells.

In any preceding embodiment, the multiport injection system provides agreater compartment pressure than electroactive zone pressure tominimize shunt current between each flow cell.

In any preceding embodiment, the power system further includes a coolingsystem for circulating a coolant in the flow cell.

In any preceding embodiment, the power system further includescomprising a level meter connected to the power storage vessel formonitoring the state of charge of the flowable semi-solid or condensedliquid ion-storing redox composition.

In yet another aspect, a method of operating a power system isdescribed, comprising:

-   -   providing power system comprising:        -   a plurality of flow cells, each flow cell comprising:            -   a positive electrode current collector,            -   a negative electrode current collector,            -   an ion-permeable membrane separating the positive and                negative current collectors;            -   wherein the positive electrode current collector and the                ion-permeable membrane define a positive electroactive                zone for accommodating the positive electrode;            -   wherein the negative electrode current collector and the                ion-permeable membrane define a negative electroactive                zone for accommodating the negative electrode; wherein                at least one of the positive and negative electrode                comprises a flowable semi-solid or condensed liquid                ion-storing redox composition in the electroactive zone                which is capable of taking up and releasing the ions                during operation of the cell;        -   at least one dispensing storage vessel for dispensing the            flowable semi-solid or condensed liquid ion-storing redox            composition into one of the positive or negative            electroactive zone; wherein the dispensing storage vessel is            connected with the plurality of flow cells and in fluidic            communication with the electroactive zone and the dispensing            vessel is capable of being connected and disconnected from            the flow cell; and        -   at least one receiving storage vessel for receiving flowable            redox composition from one of the positive or negative            electroactive zone, wherein the receiving vessel is            connected with the flow cell and in fluidic communication            with the electroactive zone and the receiving vessel is            capable of being connected and disconnected from the flow            cell;    -   introducing the flowable redox composition from the dispensing        vessel into at least one of the electroactive zones to cause the        flow cell to discharge to provide electric energy to operate the        device; and    -   receiving the discharged redox composition in the receiving        vessel.        refueling the power system by replacing the dispensing vessel        containing the redox composition with a new dispensing vessel        containing fresh flowable redox composition.

In any preceding embodiment, the method further includes replacing thereceiving vessel with a new empty receiving vessel.

In any preceding embodiment, the fresh redox composition has at leastone different characteristic from the redox composition.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different power densities.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different energy densities.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different semi-solid particle sizes.

In any preceding embodiment, the fresh redox composition and the redoxcomposition has different electroactive material concentrations.

In any preceding embodiment, the fresh redox composition has smallersemi-solid particle size and higher power density than the redoxcomposition.

In any preceding embodiment, the fresh redox composition has higherelectroactive material concentration and higher energy density than theredox composition.

In any preceding embodiment, the dispensing vessel and receiving vesselform a unitary body.

In any preceding embodiment, the plurality of flow cells form a stack offlow cells, and the dispensing and receiving vessels are reversiblyconnected with the flow cell stack.

In any preceding embodiment, the flow cells are connected in parallel.

In any preceding embodiment, the flow cells are connected in series.

In any preceding embodiment, the power system further comprises a pumpdisposed between one or both of the dispensing and receiving vessels andthe flow cell stack.

In any preceding embodiment, the pump is a reversible flow pump that isoperable for flow in both directions.

In any preceding embodiment, the dispensing or receiving vesselscomprise a flexible bladder.

In any preceding embodiment, the method further includes providingvalves positioned at the entrance of each fuel cell to control the flowof redox composition into the respective flow cell and minimize shuntcurrent between adjacent flow cells.

In any preceding embodiment, the method further includes providing amultiport injection system configured and arranged to control the amountof redox composition delivered to each electroactive zone of each flowcell.

In any preceding embodiment, the multiport injection system comprises aplurality of compartments, each compartment in flow communication with asubset of the flow cells in the flow cell stack and injectors forintroducing redox composition into each compartment.

In any preceding embodiment, the pressure in the plurality ofcompartment is greater than the pressure in the electroactive zonepressure.

In any preceding embodiment, the method further includes a coolingsystem tor circulating a coolant in the flow cell stack.

In any preceding embodiment, the method further includes providing amonitoring meter connected to one or both of the dispensing andreceiving vessels for monitoring the volume or content of the redoxcomposition in one or both of the dispensing or receiving vessel.

In any preceding embodiment, the method further includes replenishingthe dispensing vessel with fresh redox composition.

In any preceding embodiment, replenishing the dispensing vesselcomprises introducing new redox composition into the dispensing vessel.

In any preceding embodiment, the method further includes removing thedischarged redox composition from the receiving vessel.

In any preceding embodiment, removing the discharged redox compositionfrom the receiving vessel comprises emptying the receiving vessel ofdischarged redox composition.

In any preceding embodiment, the dispensing und receiving vessel form aunitary body, the unitary body having a movable membrane between thereceiving and dispensing compartments and the method further comprisesreplacing the unitary body with a new unitary body comprising a powerstorage vessel containing fresh flowable semi-solid or condensed liquidion-storing redox compositions and an empty spent redox compositionstorage vessel.

In any preceding embodiment, the method further includes monitoring thelevels of the flowable redox compositions in the dispensing or receivingvessels.

In any preceding embodiment, the method further includes

-   -   reversing the direction of flow of the redox composition so that        the spent redox composition flows from the receiving vessel to        the electroactive zone; and    -   applying a reverse voltage to the power system to recharge the        discharged redox composition.

In any preceding embodiment, the method further includes advancing therecharged redox composition from the electroactive zone to thedispensing vessel for storage.

In any preceding embodiment, the flow of the spent redox composition iscontrolled by a reversible pump.

In any preceding embodiment, the particle size of the flowablesemi-solid ion-storing redox composition being discharged is selected toprovide a preselected power density.

In any preceding embodiment, the load in wt percent of the flowablesemi-solid ion-storing redox composition being discharged is selected toprovide a preselected energy capacity of the redox composition.

In any preceding embodiment, the method further includes monitoring thecondition of the redox composition before during or after discharge.

In any preceding embodiment, the condition monitored comprises thetemperature, flow rates, or the relative amounts of the cathode or anoderedox compositions.

In any preceding embodiment, the method further includes modifying aproperty of the redox composition based on the results of themonitoring.

In any preceding embodiment, the method further includes increasing theflow rate of the redox composition along the electroactive zone toincrease the power of the flow cell.

In any preceding embodiment, the method further includes reconditioningthe flowable semi-solid or condensed liquid ion-storing redoxcomposition.

In any preceding embodiment, the reconditioning comprises

-   -   sequesting residual water from the the redox composition;    -   adding additional salt to improve ion conductivity;    -   adding solvents or electrolyte additives;    -   adding additional solid phases including active materials used        for ion storage, or conductive additives;    -   separating solid phases from the liquid electrolyte;    -   adding coagulation aids;    -   replacing the liquid electrolyte; or    -   any combination thereof.

In any preceding embodiment, at least one of the flow cells comprises:

-   -   an electrode comprising a flowable semi-solid or condensed        liquid ion-storing redox composition capable of taking up and        releasing the ions during operation of the cell; and    -   a stationary electrode.

BRIEF DESCRIPTION OF THE DRAWING

The subject matter is described with reference to the following figures,which are presented for the purpose of illustration only and are notintended to be limiting of the invention.

FIG. 1 is an illustration of a power system according to one or moreembodiments having an energy stack and interchangeable fuel vessels.

FIG. 2 is a cross-sectional illustration of an energy stack according toone or more embodiments, showing the introduction of anode slurry andcathode slurry into the stack.

FIG. 3 is a cross-sectional illustration of an energy stack having cellselectrically connected in parallel according to one or more embodiments.

FIG. 4 is a cross-sectional illustration of a plurality of energy stacksthat are electrically connected in series according to one or moreembodiments.

FIG. 5 is a illustration of a removable fuel storage system according toone or more embodiments.

FIGS. 6A-6B are illustrations of fuel tanks having a movable membraneaccording to one or more embodiments.

FIGS. 7A-C are illustrations of a fuel tank containing an anode orcathode slurry of different grades according to one or more embodiments.

FIGS. 8A-C are illustrations of a fuel tank containing an anode orcathode slurry of different power grades according to one or moreembodiments.

FIGS. 9A-9B illustrate the recharging and replacement of the anode andcathode slurry fuel tanks according to several embodiments.

FIG. 10 illustrates a multi-redox flow cell stack device according toone or more embodiments.

FIG. 11 illustrates a multi-redox flow cell stack where the flowdirections of the cathode slurry and anode slurry are reversibleaccording to one or more embodiments.

FIGS. 12A-12E illustrate a multi-cell semi-solid flow cell stack designand various types of valves that can be incorporated into the designaccording to one or more embodiments.

FIG. 13 illustrates a multi-port injection system for semi-solid flowmulti-cell stack according to one or more embodiments

FIG. 14 illustrates a plan view of one of bipolar plates of amulti-redox flow cell stack design assembled by stacked plates accordingto one or more embodiments.

FIG. 15 illustrates a semi-solid flow multi-cell stack design where themanifold is formed by stacking the plates together according to one ormore embodiments.

DETAILED DESCRIPTION

An automotive or other power system including a flow cell, in which thestack that provides power is readily isolated from the storage vesselsholding the cathode slurry and anode slurry (alternatively called“fuel”) is described. A method of use is also provided, in which the“fuel” tanks are removable and are separately charged in a chargingstation, and the charged fuel, plus tanks, are placed back in thevehicle or other power system, allowing fast refueling. The technologyalso provides a charging system in which discharged fuel is charged. Thecharged fuel can be placed into storage tanks at the power source orreturned to the vehicle. In some embodiments, the charged fuel in thestorage tanks can be used at a later date. The charged fuel can betransported or stored for use in a different place or time.

A power system according to one or more embodiments includes a redoxflow battery in which at least one of the positive electrode or anodeslurries of the fuel is semi-solid or is a condensed liquid reactant,and in which at least one of the electrode-active materials istransported to and from an assembly at which the electrochemicalreaction occurs, producing electrical energy. By “semi-solid” it ismeant that the material is a mixture of liquid phase and solid phases,such a mixture also being known as a slurry, particle suspension,colloidal suspension, emulsion, or micelle. In some embodiments, thesolid constituents of the semi-solid comprise at least one material thatundergoes reaction or alloying or intercalation with the working ions ofthe battery to generate or store electrical energy. As a result, duringthe operation of the cell, the electroactive material of the redoxcouple can remain in the semi-solid in both of its oxidative stateswithout going into solution. Therefore, the solubility of theelectroactive material no longer limits its concentration in theelectroactive zone, resulting in a large increase of the effectiveconcentration of the electroactive materials in the flow cell. As aresult, the energy density of the cell using semi-solid redoxcomposition is greatly increased. The liquid supporting theelectroactive component can be aqueous or non-aqueous. In someembodiments the redox flow buttery comprises a non-aqueous cell,including but not limited to an alkali ion rechargeable cell wherein theworking ion is an alkali ion. Solvents typically used as electrolytesolvents may be used as the liquid in the semi-solid cathode or anodeslurries. As used herein, condensed liquid or condensed ion-storingliquid refers to a liquid that is not merely a solvent as it is in thecase of an aqueous flow cell catholyte or anolyte, but rather that theliquid is itself redox-active. The liquid form can also be diluted by ormixed with another, non-redox-active liquid that is a diluent orsolvent, including mixing with such a diluents to form a lower-meltingliquid phase, emulsion or micelles including the ion-storing liquid.Similarly, during the operation of the cell, the working ion of theredox couple can remain in the condensed liquid phase in both of itsoxidative states without going into solution. Therefore, the solubilityof the electroactive material no longer limits its concentration in theelectroactive zone, resulting in a large increase of the effectiveconcentration of the electroactive materials in the flow cell. As aresult, the energy density of the cell using condensed liquid redoxcomposition is greatly increased.

In some embodiments the redox flow battery is a lithium battery ofprimary or rechargeable type. In some embodiments at least one of theenergy storing electrodes comprises a condensed liquid of a redox activematerial, including but not limited to lithium metal, gallium and indiumalloys, molten transition metal chlorides, thionyl chloride, and thelike. Further information on redox batteries may be found in co-pendingprovisional patent application No. 61/060,972, filed Jun. 12, 2008,entitled “High Energy Density Redox Flow Battery”, which is incorporatedherein in its entirety by reference.

One distinction between a conventional flow battery anolyte andcatholyte and the ion-storing solid or liquid phases as exemplifiedherein is the molar concentration or molarity of redox species in thestorage compound. For example, conventional anolytes or catholytes thathave redox species dissolved in aqueous solution may be limited inmolarity to typically 2M to 8M concentration. Highly acidic solutionsmay be necessary to reach the higher end of this concentration range. Bycontrast, any flowable semi-solid or condensed liquid ion-storing redoxcomposition as described herein may have, when taken in moles per literor molarity, at least 10M concentration of redox species, preferably atleast 12M, still preferably at least 15M, and still preferably at least20M, because the solubility of the electroactive materials no longerlimits it concentration in the flow cell. The electrochemically activematerial can be an ion storage material or any other compound or ioncomplex that is capable of undergoing Faradaic reaction in order tostore energy. The electroactive material can also be a multiphasematerial including the above-described redox-active solid or liquidphase mixed with a non-redox-active phase, including solid-liquidsuspensions, or liquid-liquid multiphase mixtures, including micelles oremulsions having a liquid ion-storage material intimately mixed with asupporting liquid phase. In the case of both semi-solid and condensedliquid storage compounds for the flowable ion-storing redoxcompositions, systems that utilize various working ions arecontemplated, including aqueous systems in which H⁺ or OH⁻ are theworking ions, nonaqueous systems in which Li⁺, Na⁺, or other alkali ionsare the working ions, even alkaline earth working ions such as Ca²⁺ andMg²⁺, and Al³⁺. In each of these instances, a negative electrode storagematerial and a positive electrode storage material may be required, thenegative electrode storing the working ion of interest at a lowerabsolute electrical potential than the positive electrode. The cellvoltage can be determined approximately by the difference in ion-storagepotentials of the two ion-storage electrode materials.

In some embodiments the “stack” or electricity generating portion of thebattery is reversibly coupled to vessels or containers holding thecathode slurry and anode slurry. The power system is illustrated inFIG. 1. The power system includes an energy stack 100 that containelectrodes and chambers for flowing the anode slurry and cathode slurry.The anode slurry is pumped from vessel 120 by a pump (not shown) throughan entry conduit 130 into the energy stack. The conduit 130 and vessel120 and are fitted with quick disconnect fittings 140 that permit therelease and connection of the vessel to the power system. Similarly, thecathode slurry is pumped from a vessel 150 by pump (not shown) throughan entry conduit 160 into the energy stack. The conduit 160 and vessel150 and are fitted with quick disconnect fittings 170 that permit therelease and connection of the vessel to the power system. The consumedor ‘spent’ anode slurry and cathode slurry in removed from the stackusing exit conduits 135 and 165, respectively. Exit conduits are alsofitted with quick release fittings (not shown). Energy stack 100 mayoptionally have a quick disconnect fitting 155, 155 as well. Thus, thevessel or fuel container is removable from the system and may be easilyreplace or refilled when the anode slurry or cathode slurry is consumedor ‘spent.’ In some embodiments, redox composition fluid is circulatedconstantly through the flow cell while being slightly charged anddischarged with each pass.

The conduit can be rigid or flexible and can be prepared fromconventional materials capable of withstanding a range of temperatureconditions and which are chemically stable in contact with the slurries.Exemplary materials include metals such as copper or brass or stainlesssteel, elastomers, polyolefins, and fluoropolymers such as Teflon™. Thefittings may be any conventional fitting used to connect and disconnecttubing or piping, selected to provide a hermetic seal and to bechemically stable in contact with the slurries of the invention.Exemplary fittings include those commonly referred to as quickdisconnect hose fittings or hydraulic quick disconnect couplers.

FIG. 2 is a cross-sectional view of an interior portion of the energystack illustrating the intake manifolds for the anode slurry and cathodeslurry. The energy stack includes a plurality of cells, each containinga positive electrode 200 in contact with cathode slurry 210, a negativeelectrode 220 in contact with anode slurry 230, and ionically conductivemembrane 240 separating the anode slurry from the cathode slurry. In oneor more embodiments, the electrodes are in contact with the respectiveanode and cathode slurries on both faces of the electrode. Thus, thecells can be efficiently arranged in facing arrangement as is known inthe art for solid batteries. Each cell includes an anode slurry inlet250 to permit inflow of anode slurry and a cathode slurry inlet 260 topermit flow of cathode slurry. The anode slurry inlets may be part of amanifold having a single inlet source 270 from anode slurry vessel 120.The cathode slurry inlets may be part of a manifold having a singleinlet source 280 from anode slurry vessel 120. The flow divide can occurinside or outside of the energy stack.

The energy stack can be arranged to provide a plurality ofelectrochemical cells that are electrically connected in parallel or inseries to provide a power system having a desired set of properties.Battery packs get their desired operating voltage by connecting severalcells in series. For example, electrochemical cells that are connectedin series will result in a cell in which the overall voltage of thesystem is the sum of the individual cell voltages. If higher capacityand current handling is required, the cells are connected in parallel.Some packs have a combination of serial and parallel connections.

FIG. 3 is a cross-sectional view of an electrical stack in which thecells of the stack are electrically connected in parallel. The stackincluding a plurality of positive current collectors 200 are joined at apositive terminal 300. Likewise, the plurality of negative currentcollectors 220 are joined at negative terminal 310. Individual energystacks can be further connected, either in series or in parallel toprovide the desired battery performance.

FIG. 4 is a perspective view of a plurality of energy stacks 400, 410,420 that are joined in series. The individual cells of the energy stackmay be joined in series or parallel. The power system can include anynumber of individual energy stacks to provide the desired voltage.

In operation, each of the energy stacks has a manifold to distribute theinput cathode slurry and anode slurry to the individual cells as shownin FIGS. 2 and 3. If a number of stacks are present, there would be amain cathode slurry flow line that goes to the cathode input on each ofthe stacks. A main anode slurry flow line can be used similarly with theanode slurry.

According to one or more embodiments, the flow cell stack is intergratedinto an energy system. FIG. 10 illustrates a multi-redox flow cell stackdevice 1001. As shown in FIG. 10, the multi-cell stack device includesend electrodes 1019 (anode) and 1020 (cathode) at the end of the device,as well as one or more bipolar electrodes such as 1021. Between theelectrodes, the multi-cell stack device also includes anode slurrycompartments such as 1015 and cathode slurry compartments such as 1016.The two compartments are separated by ionically conductive membranessuch as 1022. This arrangement is repeated to include multi-cell designin the device. As least one of the anode slurry and cathode slurry inthe anode slurry and cathode slurry compartments contain semi-solid orcondensed liquid as described above. Bipolar electrode 1021 includes acathode (cathode current collector) 1025 which faces the cathode slurrycell compartment 1016 and an anode (anode current collector) 1026 whichfaces the anode slurry cell compartment 1027. A heat sink or a insulatorlayer 1028 is disposed in between cathode 1025 and anode 1026. In someembodiments, the heat sink comprises a coolant. The electrodearrangement described here in FIG. 10 is different from that in FIG. 2and represent an alternative design of the multi-redox flow cell slack,i.e., individual cells instead of face to face cells.

The current collector (electrode) is electronically conductive andshould be electrochemically inactive under the operation conditions ofthe cell. Typical current collectors for lithium redox flow cellsinclude copper, aluminum, or titanium for the negative current collectorand aluminum for the positive current collector, in the form of sheetsor mesh, or any configuration for which the current collector may bedistributed in the electrolyte and permit fluid flow. Selection ofcurrent collector materials is well-known to those skilled in the art.In some embodiments, aluminum is used as the current collector forpositive electrode. In some embodiments, copper is used as the currentcollector for negative electrode.

The membrane can be any conventional membrane that is capable of iontransport. In one or more embodiments, the membrane is aliquid-impermeable membrane that permits the transport of ionstherethrough, namely a solid or gel ionic conductor. In otherembodiments the membrane is a porous polymer membrane infused with aliquid electrolyte that allows for the shuttling of ions between theanode and cathode electroactive materials, while preventing the transferof electrons. In some embodiments, the membrane is a microporousmembrane that prevents particles forming the positive and negativeelectrode flowable compositions from crossing the membrane. Exemplarymembrane materials include polyethyleneoxide (PEO) polymer in which alithium salt is complexed to provide lithium conductivity, or Nafion™membranes which are proton conductors. For example, PEO basedelectrolytes can be used as the membrane, which is pinhole-free and asolid ionic conductor, optionally stabilized with other membranes suchas glass fiber separators as supporting layers. PEO can also be used asa slurry stabilizer, dispersant, etc. in the positive or negativeflowable redox compositions. PEO is stable in contact with typical alkylcarbonate-based electrolytes. This can be especially useful inphosphate-based cell chemistries with cell potential at the positiveelectrode that is less than about 3.6 V with respect to Li metal. Theoperating temperature of the redox cell can be elevated as necessary toimprove the ionic conductivity of the membrane.

In some embodiments, a bipolar electrode includes a cathode and an anodeseparated by a coolant region for introducing a coolant through thebipolar electrode. Non-limiting examples of coolants include ethyleneglycol and water.

The multi-cell stack device is connected to an anode slurry storage tank1002 which stores the anode slurry. As shown in FIG. 10, a positivedisplacement pump 1004 is used to pump anode slurry through a flow meter1006 and a check valve 1007 into a manifold 1013, which delivers theanode slurry into multiple anode slurry cell compartments such as 1015.The discharged anode slurry is removed through manifold 1017, flow valve1011 and back into the tank 1002. Similarly, a positive displacementpump 1005 is used to pump cathode slurry from storage tank 1003, througha flow meter 1023 and a check valve 1024 into a manifold 1014, whichdelivers the cathode slurry into cathode slurry cell compartments suchas 1016. The discharged cathode slurry is removed through manifold 1018,flow valve 1012 and back into the tank 1003.

A positive displacement pump causes a fluid to move by trapping a fixedamount of it then forcing (displacing) that trapped volume through thepump. Positive displacement pump 1004 or 1005 can minimize the loss ofthe fluid through the pump, and any positive displacement pump known inthe art can be used. In addition, other means of fluid transport can beused. Flow meter 1006 or 1023 measures and controls the amount of anodeslurry or cathode slurry that is pumped into the cell compartments. Anytype of flow meter known in the art can be used. Non-limiting examplesof flow meters include electric flow meters, turbine flow meters, massflow meters and positive displacement flow meters. Check valves 1007 and1024 are used to prevent the back flow of the fluids. Any check valvesknown in the art can be used. Non-limiting examples of flow valves 1011and 1012 include any mechanical or electrical valves. Flow valves arefurther discussed in greater details in FIG. 13. Optionally, a levelmeter 1008 can be connected to the storage tank 1002 or 1003 to monitorthe levels of the cathode slurry or anode slurry inside the tank.Temperature monitors 1010 and pressure monitors 1009 can also beconnected to the storage tank to monitor the temperature and pressurewithin the tank.

FIG. 11 illustrates a multi-redox flow cell stack device 1101 where theflow directions of the cathode slurry and anode slurry are reversible.The reversible nature of the pumps allows the discharge and recharge ofthe electroactive slurry to take place in situ. The multi-cell stackdevice also includes anode slurry compartments such as 1115 and cathodeslurry compartments such as 1116. The two compartments are separated byionically conductive membranes such as 1122. As least one of the anodeslurry and cathode slurry in the anode slurry and cathode slurrycompartments contain semi-solid or condensed liquid as described above.

As shown in FIG. 11, the multi-redox flow cell 1101 is connected toanode slurry storage tank 1102 and cathode slurry storage tank 1104.Anode slurry storage tank 1102 further contains a bladder 1103. Duringoperation (discharge of the device), the charged anode slurry in storagetank 1102 is pumped, in the direction as indicated by arrow 1108, byusing a reversible flow pump 1106. The anode slurry passes flow meter1117, flow valve 1118 and into the manifold 1110. The manifold 1110delivers charged anode slurry into anode slurry cell compartments suchas 1115. After use, the discharged anode slurry can be removed throughmanifold 1115 and pumped through valve 1119 into bladder 1103 forstorage. During charging of the device, the flow direction within thereversible flow pump 1106 is reversed and the discharged anode slurry inbladder 1103 can be pumped, in the direction as indicated by arrow 1109,through valve 1119 and into manifold 1115, which delivers the dischargedanode slurry into the anode slurry compartments such as 1115. A voltageis then applied to the device and the discharged anode slurry can berecharged.

Similarly, cathode slurry storage tank 1104 further contains a bladder1105. During operation (discharge of the device), the charged cathodeslurry in storage tank 1104 is pumped, in the direction as indicated byarrow 1111, by using a reversible flow pump 1107. The cathode slurrypasses flow meter 1120, flow valve 1121 and into the manifold 1113. Themanifold 1113 delivers charged cathode slurry into cathode slurry cellcompartments such as 1116. After use, the discharged cathode slurry canbe removed through manifold 1114 and pumped through valve 1123 intobladder 1105 for storage. During charging of the device, the flowdirection within the reversible flow pump 1107 is reversed and thedischarged cathode slurry in bladder 1105 can be pumped, in thedirection as indicated by arrow 1112, through valve 1123 and intomanifold 1114, which delivers the discharged cathode slurry into thecathode slurry compartments such as 1116. A voltage is then applied tothe device and the discharged cathode slurry can be recharged. The flowvalves and flow meters are as described above.

The semi-solid or condensed liquid anode slurry or cathode slurry asdescribed above are electrically conductive materials. Thus, duringoperation of the device, shunt current may occur to bypass one or morecell compartments and/or bipolar electrodes in the device. For example,the current can go through the cathode slurry or anode slurry in themanifold to bypass one or more cell compartments and/or bipolarelectrodes in the device. When a bipolar stack comprising multipleindividual cells is used, the occurrence of shunt current from cathodeto cathode and anode to anode will decrease the stack voltage. In one ormore embodiments, non-conductive valves can be introduced at the inletor outlet position of the manifold to reduce or prevent the shuntcurrent.

FIG. 12 illustrates a multi-cell semi-solid flow cell stack design andvarious types of valves that can be incorporated into the design. FIG.12A illustrates a multi-cell semi-solid flow cell stack design 1201which includes end-electrodes 1209 and 1211, bipolar electrodes such as1210 and 1212, membranes such as 1213 which separates anode slurry cellcompartment 1215 and cathode slurry cell compartment 1214. Valves suchas 1202 are positioned at one of the inlet positions of the manifold1204, which delivers cathode slurry into the cathode slurry cellcompartment 1214. Valves such as 1216 are positioned at one of the inletpositions of the manifold 1203, which delivers anode slurry into theanode slurry cell compartment 1215. Valves such as 1202 and 1216 arenon-conductive thus can prevent the shunt current through the manifold.In one or more embodiments, such valves are pulsating valves and openfor only a short period of time to allow the anode slurry or cathodeslurry to pass through quickly without resulting in any shunt current.In one or more embodiments, additional valves are positioned at theoutlet position 1207 of manifold 1206 and at the outlet position 1208 ofmanifold 1205.

The valves described above are any mechanical or electrical operatedvalves. In some embodiments, the valve is a solenoid valve. Non-limitingexamples of suitable non-conductive valves are illustrated in FIGS.12B-12E. FIG. 12B illustrates the open and close forms of a valveincluding a ball-like switch. The valve is activated by pressuredifferentiation of the two side of the valves. FIG. 12C illustrates theopen and close forms of a valve including a coin-like switch. The valveis activated by pressure differentiation of the two side of the valves.FIG. 12D illustrates the open and close forms of a valve including aflapper-like switch. The valve can be activated by a spring mechanism toallow the fluid flow. The valve can also by activated by a double-springmechanism to reverse the direct of the flow. Such spring mechanism canbe controlled mechanically or electrically. Different types of heartmechanical valves can also used. FIG. 12E illustrates the open and closeforms of a valve including a membrane switch. The membrane is made outof “shape memory membrane material” which changes its shape whenactivated. The membrane-switch can be activated electrically. Otherexamples include tissue valves which can be electrically activated.Other valves known in the art are also contemplated.

FIG. 13 illustrates a multi-port injection system for semi-solid flowmulti-cell stack. A multi port injection system can precisely controlthe amount of fluid being delivered to each “plenum” or cellcompartment. If a group of cells need more fluid to increase the voltagea multi-port injection will be able to accomplish this without affectingthe other compartments. Increase fluid flow accuracy and controls. Asshown in FIG. 13, the multi-flow cell design includes injectors such as1301 (in manifold 1302) and 1305 (in manifold 1307). During operation,the anode slurry is introduced into manifold 1302 and injected intoplenum region 1303 by injectors such as 1301. The plenum region 1303 ispressurized so that the anode slurry, once injected into anode slurrycell compartment 1308, will not back-flow into the manifold 1303.Similarly, the cathode slurry is introduced into manifold 1307 andinjected into plenum region 1306 by injectors such as 1305. The plenumregion 1306 is pressurized so that the cathode slurry, once injectedinto cathode slurry cell compartment 1309, will not back-flow into themanifold 1307. Because the flow direction is controlled, the shuntcurrent through the manifold is also minimized. Such configuration canreduce or minimize the shunt current between fluids in different“plenums”. Pressure transducers such as 1304 are included in themanifold to monitor and control the pressure within the manifold.

In one or more embodiments, the inside of the manifold used to delivercathode and anode slurries and, optionally, coolant, is coated withnon-conductive materials to minimize shunt current across the fluids. Inone or more embodiments, the manifold itself is made of an electricallyinsulating material such as a polymer or ceramic.

FIG. 14 illustrates a plan view of one of bipolar plates of amulti-redox flow cell stack design assembled by stacked plates such asdescribed above with reference to FIG. 10. As shown in FIG. 14, theplate includes an active region 1401 which comprises a cathode currentcollector or an anode current collector. Region 1402 includes opening1404 which is used as part of the manifold to deliver anode slurry intothe anode slurry cell compartment. Region 1402 also includes opening1405 which is used as part of the manifold to deliver cathode slurryinto the cathode slurry cell compartment. Region 1402 also optionallyincludes opening 1406 which is used as part of a manifold to delivercoolant into the bipolar electrode. Region 1403 includes opening 1407which is used as part of the manifold to remove cathode slurry from thecathode slurry cell compartment. Region 1403 includes opening 1409 whichis used as part of the manifold to remove discharged anode slurry fromthe anode slurry cell compartment. Region 1403 also optionally includesopening 1408 which is used as part of a manifold to remove coolant fromthe bipolar electrode. Optionally, a channel (not shown) disposedbetween the two electrodes of the bipolar electrode is used to hold thecoolant and is connected with openings 1406 and 1408. The plates whichcomprise cell compartments and membranes between the electrodes alsocomprises similar openings as those described in FIG. 14. The bipolarplates such as 1410 and end electrode plates as described are alignedtogether, stacked with cell compartments and membranes in between andform a semi-solid flow multi-cell stack 1501 as illustrated in FIG. 15,with all the corresponding openings of different plates properlyaligned. Manifold 1502 is formed by stacking the plates together andaligning similar openings on each plate accordingly. Manifold 1502 isused to introduce anode slurry into the anode slurry cell compartment.Similarly, manifold 1503 is formed to introduce cathode slurry into thecathode slurry cell compartment. Manifolds 1505 and 1504 are also formedto remove anode slurrys and cathode slurry from the cell compartments,respectively. Optionally, channels or manifolds such as 1506 and 1507are also formed, which are used for introducing and removing the coolantfrom the device, respectively. The inside of the openings 1405, 1406,1407, 1408, 1409, and 1410 can be coated with non-conductive materials.Thus, the manifolds formed for anode slurry, cathode slurry, andoptionally coolant all have non-conductive inside thus minimizedunwanted, parasitic shunt currents to flow through anode slurry, cathodeslurry, and the coolant. Any non-conductive coating known in the art canbe used. Non-limiting examples of the non-conductive coatings includenon-conductive polymers such as epoxies, polyamide-imides, polyetherimides, polyphenols, fluro-elastomers, polyesters, phenoxy-phenolics,epoxidephenolics, acrylics and urethanes.

With reference to FIG. 5, a feature of the power system using redox flowcells as the energy and power source is that the anode slurry andcathode slurry can be introduced into the energy stack at a high stateof charge, that is, the electroactive components of the system is fullycharged. During operation, anode slurry and cathode slurry flow, e.g.,are pumped, into the energy stack 500 from fuel storage vessels 510 and520, respectively, and into individual cells and flow past currentcollectors. The redox-active ions or ion complexes undergo oxidation orreduction when they are in close proximity to or in contact with aconductive electrode or current collector that typically does not itselfundergo redox activity. During these reactions, the redox-activematerials discharge, e.g., the state of charge diminishes. As the anodeslurry and cathode slurry exit the energy stack, the state of charge isreduced and the anode slurry and cathode slurry are ‘spent.’ The spentsuspensions are then collected in spent fuel storage vessels 530 and540, respectively. When the fuels cells 510 and 520 are empty, and spentfuel tank 530 and 540 are full, they can be swapped out and replacedwith fresh containers of fuel and empty spent fuel containers. In thismanner, the device being powered by the power system, e.g., an electricor hybrid electric motor vehicle, is refueled.

In some embodiments, the fuel containers are adapted to both deliver thefresh fuel and accept the spent fuel, as shown in FIG. 6A. FIG. 6A is aperspective view of tank 600 that can be used for delivering eitheranode slurry or cathode slurry to the energy stack, and receiving thespent fuel. Tank 600 includes an upper chamber 610 and a lower chamber620. The upper chamber is in flow communication with the intake manifoldof the cathode slurry or anode slurry through conduit 615. Once the fuelhas been consumed in the energy stack, it exits the stack and returns tothe lower chamber 620 through conduit 625. Tank 600 includes a moveableinner wall or membrane 628 that can move up and down in the tankinterior to increase or decrease the size of the two interior chamber toadjust for the constantly changing relative volume of liquid in the twochambers. In some embodiments the membrane is selected to be flexibleover the temperature range of use, sufficiently strong to withstand theforces and pressures encountered in use, chemically stable in contactwith the components of the cathode and anode slurries, and impermeableor permeable to the electrolyte.

In still yet another embodiment, a single tank 700 is used for the outflow and uptake of both anode slurry and cathode slurry. In FIG. 6B,tank 700 includes upper chambers 710 and 720 for housing fresh anodeslurry and cathode slurry, respectively. The tank also includes lowerchambers 750 and 760 for receiving spend anode slurry and cathodeslurry, respectively. As in the single fuel canisters described in FIG.6A, the tank can include a moveable membrane or wall 730, 740 that movesin response to the relative change in volume of fresh and spent fuels.The two membranes can move together or independently. In use, the freshanode slurry is fed into the energy stack from conduit 765; similarly,the fresh cathode slurry is fed into the energy stack from conduit 775.After use, the spent anode slurry and cathode slurry return to tank 700through conduits 785 and 795, respectively. Wall 715 separates the anodeslurry from the cathode slurry and may be stationary or moveable.

The particular type of tank used may depend on the intended use of thepower system. For systems with adequate storage room in the engine, thefour tank system described in FIG. 5 can be used and may be mostappropriate for providing large volume of fuel, which permits longerdistances before refueling. On the other hand, the one tank, fourcompartment tank described in FIG. 6B is compact and occupies lessspaced. It can easily be swapped out in a single step. The tank, withits additional elements and moving parts, is more expensive to make anduse.

Another feature of the redox composition is the availability of various“grades” of “fuel” or slurry. For example, a premium grade of fuel mayinclude a cathode slurry or anode slurry or both that provides higherpower, or longer operational time and therefore driving range, or both,in the same volume of “fuel.” Compared to an internal combustion enginepowered vehicle, where the differences in power between “regular” and“premium” gasoline are often not detectable or are very subtly differentto the consumer, the differences in power and range provided by properlyengineered slurries can be very dramatic—the power may be 10% or 20% or50% or even 100% greater for one slurry than another, as may be thedriving range, for the same size “gas tank.”

Thus, one use model of the invention is to provide, within the samevolume or size of “fuel tank” or total system size including stacks,widely varying performance capabilities. FIG. 7 illustrates varying fuelgrade in tanks of the same size. The fuel can range from a low gradefuel having a low fuel mileage range (7A) to a medium “plus” grade fuelhaving a medium mileage range (7B) and even can include a “premium”grade of higher grade fuel that provides the best mileage range (7C).The grades of fuel can be adjusted by changing a number of variables inthe cathode and anode slurries. For example, the number or density ofelectrode particles in a slurry can be adjusted in order to adjust thecharge capacity per unit volume of slurry, with higher particle densityhaving greater charge capacity and longer driving range. This isillustrated in FIGS. 7A-7C, which illustrates fuel tanks of the samesize having an increased density of particles with increasing fuelgrade. By way of example, a lithium iron phosphate or lithium cobaltoxide based fuel system can be prepared at particle densities thatprovide a total volume percentage of the active material in the slurryranging from about 20 volume % to about 70 volume %. The additionalparticle density is typically accompanied by a change in viscosity orrheology of the slurries, which may necessitate a change in the pumpingprocedure such as pumping rate or intermittency of pumping. In yet otherembodiments, the range of regular, plus and premium ranges of fuel canbe obtained by using different electroactive materials having differentcharge capacities.

In yet another embodiment, the power of the fuel is modified and theconsumer may select between regular, plus power and premium powerbatteries. In FIG. 8, fuel grades based on power is illustrated. Thepower system may be able to operate using anode and cathode slurrieshaving different power, e.g., the delivery of larger or smaller amountsof energy per unit time. The power of the anode or cathode slurries canbe varied by modifying the particle size of the electroactive particlesin the slurry. A smaller particle size would have a greater surface areaand therefore a greater amount of working surface available per unitmass, as well as a smaller dimension through which the solid-statetransport of lithium takes place, thereby providing higher dischargepower. Thus, by way of example, a lithium iron phosphate based cathodemay be prepared in average crystallite sizes of 30 nm, 50 nm, and 100nm, and a corresponding graphite based anode slurries may containparticle sizes of 1 micrometer, 5 micrometers, und 20 micrometers. Thecrystallite size is not necessarily the same as the particle size sinceparticles may consist of agglomerates or aggregates of individualcrystallites. In other embodiments, the electroactive materials of theslurries may be varied to provide different power capabilities in thedifferent fuel systems.

Another use model is to provide to the consumer various tank sizes.Unlike a conventional vehicle in which the size of the fuel tank isdetermined at time of manufacturing, in the present invention theability to readily exchange slurry tanks for refueling, one can providetanks of different sizes for different needs. For example, a consumermay purchase a larger tank of fuel, and give up some storage space in acar, when taking a longer trip.

The ability to conveniently exchange the fuel tanks provides severaloptions for recharging, as illustrated in FIG. 9A-9B. The spent cathodeand anode slurries typically contain electroactive materials developedfor standard secondary batteries and may be recharged under conditionsthat are similar to those developed for those materials in standardsecondary battery formats. Thus, a consumer may recharge the spent anodeand cathode slurries while the fuels are hooked up to the power system,by plugging the power system into an alternative power source, e.g., awall outlet, and initiating a recharging cycle in the power system. Thetwo slurries are pumped in the reverse direction while charging, and arestored, presumably in the original tanks. No other components need to beadded as long as the pumps/valves work in both directions. In otherembodiments, one can have a separate slurry flow circuit to bring theslurries back through the stack during charging, if there is a need touse one-way valves.

In other embodiments, for example, when traveling or short on time, theuser can swap fuel tanks at a recharging station. The user returns spentfuels at a recharging station and receives fresh slurries. The chargingstation can replace the fuel tanks (like the model used for refillingpropane tanks) or simply empty and refill the existing tanks. Theability to swap fuel tanks would provide flexibility in the type of fueland fuel capacity available to the user, as discussed above. The usercan change grade, power or tank capacity from refill to refill.

In conventional batteries the cathode/anode ratio is fixed at the timeof manufacturing and cannot be changed if the operating conditions ofthe battery require it, such as if at high power one of the electrodeshas slower kinetics and therefore more of that electrode would beadvantageous. In a power system as described herein, the properties ofthe power system can be varied or altered as needed.

In one or more embodiments, the flow rates of the cathode and anodeslurries can be different. For example, a lithium phosphate-busedcathode suspension used with a graphite anode suspension may berate-limited by the lithium uptake capability of the anode because toofast a charge rate may result in Li plating at the anode. However, byflowing the anode slurry at a higher rate than the cathode slurry undersuch high power charge conditions, the plating can be avoided. Also, thevoltage of the cell will remain higher because anode slurry will exitthe stack at a higher state of charge.

In another embodiment, the flow rates of the cathode and anode slurries,or Cathode/Anode ratio in-situ, can be varied to accommodate anydegradation of the electrode slurries that occurred during use. Ratherthan simply replacing or discarding the slurry, it may be used at adifferent flow rate to improve the performance of the cell, for example,keeping performance within specifications, even if lower than with newslurries. That is, the operating life of the cell can be improved andextended by increasing the flow rate of one or both slurries, or bychanging the Cathode/Anode ratio up or down.

Another operational mode that is advantageous in the redox compositionis that power can be improved when needed. In one or more embodiments,the cell voltage is maintained at a relatively higher level byincreasing the flow rate of both slurries, so that each is operating ata high state of charge during periods of higher power demand. The energyavailable in the slurries may not be fully utilized during suchoperational periods, but the power can be improved. Of course, this canbe accomplished by increasing the flow rate of just one electrode slurryas well to keep that slurry at higher rate.

In one or more embodiments, the stack includes monitoring devices thatprovide the power system or a power management system with informationconcerning the condition of the power system. This information may beused, in real time or prior to use, to select the optimal operatingconditions of the power system. By way of example, the temperature, flowrates, and relative amounts of the cathode and anode slurries can becontrolled.

Another use model is to evaluate, replenish, or recondition the fuelslurries at a service provider or manufacturer at one or more times inthe life of the fuel slurries. In a conventional battery, the electrodescannot be reconditioned during the battery's life. In the redox powersystem, each slurry can be reconditioned to restore or extend thebattery life. When a power system is first brought into the servicestation, the fuel may first be tested at the service provider toevaluate its condition when it is returned for charging or service.Secondly, it can be reconditioned in several ways. For example, residualwater may be sequestered from the suspension. Additional salt to improveion conductivity may be added. Solvents or electrolyte additives may beadded. Additional solid phases including active materials used for ionstorage, or conductive additives, may be added. The solid phases may beseparated from the liquid electrolyte, for example by filteringcentrifugation, or the addition of coagulation aids to cause the solidphases to be less well suspended. The solids or solid-enrichedsuspension and the separated liquid electrolyte may be individuallytreated, or even replaced.

Of course, any combination of replenishing or reconditioning steps maybe performed as well. Doing so can decrease the expense of the systemover its useful life by selectively replacing or reconditioning specificfailed components, improve lifetime or performance as new additives orcomponents are discovered, or aid in the recycling of the materials.

Another use model is to replace the power “stack” of the flow batteryseparately from the fuel tanks or other components. Unlike aconventional battery, the ability to replace only certain components asthey degrade, or as upgrades are desired, provides economic advantagesto both the user and the service provider or manufacturer. Thus, in oneor more embodiments, the energy stack is removed from the power systemand is replaced or repaired.

In another aspect, the power system can include an electrical energystorage device and power source that is simultaneously a conventionalrechargeable battery and a flow cell in one integrated device. It isapplicable to various battery chemistries, including aqueous batteriessuch as nickel metal hydride types, and nonaqueous batteries includinglithium rechargeable batteries, sodium rechargeable batteries, orbatteries based on other alkali or alkaline earth or non-alkalineworking ions. Considering one embodiment based on lithium ion chemistry,the basic construction of such a cell has a separator, on one side ofwhich is a lithium battery positive electrode or a negative electrode,or both, as in a conventional rechargeable lithium battery. That is, theelectrodes comprise cathode or anode active material, and may comprise acoating of the active material on a metallic current collector, or maybe a stand-alone electrode layer such as a densified or sintered layercomprising the active material, optionally with other constituents suchas polymer binders or carbonaceous conductive additives or metallicadditives or binders. These ion-storage electrodes will be referred toas the stationary electrodes. However, unlike a conventional lithiumbattery electrode, one or both of the stationary electrodes is permeableto a flow cell cathode slurry or anode slurry, so that during operationof the device, it is possible to charge or discharge only the activematerials on the stationary electrode, only the flow cell cathode slurryor anode slurry, or both.

One embodiment of the invention uses a cathode slurry or anode slurrythat is a semi-solid fluid, or suspension, or slurry, as described inprevious filings.

In one embodiment, one or both of the stationary electrodes areimmediately adjacent to the separator layer, including being coated onthe separator. As in a conventional battery, this permits relativelyrapid charge and discharge of the battery using the working ions storedin the stationary electrodes. In addition, the ions stored in thecathode slurry and anode slurry are also available to the device and canbe charged and discharged, although this may occur at a differentkinetic rate than the stationary electrodes. Such a design allows thesingle device to provide a high power charge or discharge for arelatively shorter period of time, while also having the high energyprovided by the flow cell aspects of the design. Thus the stationaryelectrodes are situated between the separator and the flow cellreactants, and optionally may also serve as the current collectors forone or more of the flow cell reactants. Another advantage of such adesign is that the stationary electrodes can provide mechanical supportto the separator layer or reduce abrasion or wear of the separator whenthe cathode slurry and anode slurry are in the form of a semi-solidfluid or suspension or slurry.

In another embodiment, one or more of the flow cell reactants flow inbetween the separator layer and the stationary electrodes.

In either case, as the stationary electrodes are charged or discharged,the flow cell cathode slurry or anode slurry can add or remove workingions from the stationary electrodes. For example, after a high powerdischarge pulse, the stationary negative electrode may be relativelydepleted, and the stationary positive electrode relatively saturated,with the working ions. The flow cell cathode slurry and anode slurry canexchange ions with the stationary electrodes to bring the entire cellback towards a charged state, from which it is able to provide anotherhigh power discharge pulse. Thus this design can provide high pulsepower capability, as is required for electric vehicles, while alsoproviding the high storage energy characteristics of a flow cell.

Upon review of the description and embodiments of the present invention,those skilled in the art will understand that modifications andequivalent substitutions may be performed in carrying out the inventionwithout departing from the essence of the invention. Thus, the inventionis not meant to be limiting by the embodiments described explicitlyabove, and is limited only by the claims which follow.

The invention claimed is:
 1. A bipolar electrochemical cell, comprising:a terminal anode current collector; a first ion-permeable membranespaced from the terminal anode current collector and at least partiallydefining a first anode; a bipolar electrode spaced from the firstion-permeable membrane and at least partially defining a first cathodebetween the first ion-permeable membrane and a first surface of thebipolar current collector; a second ion-permeable membrane spaced fromthe bipolar current collector and at least partially defining a secondanode between the second ion-permeable membrane and a second surface ofthe bipolar current collector; and a terminal cathode current collectorspaced from the second ion-permeable membrane and at least partiallydefining a second cathode between the terminal cathode current collectorand the second ion-permeable membrane, wherein at least one of the firstanode, the second anode, the first cathode, and the second cathodeincludes a semi-solid or condensed liquid ion-storing redox composition,the semi-solid or condensed liquid ion-storing redox compositionincluding a conductive additive and an ion-storing solid phase; whereina volume percentage of the ion-storing solid phase is between 20% and70%, and wherein the semi-solid or condensed liquid ion-storing redoxcomposition is capable of taking up or releasing ions, and remainssubstantially insoluble during operation of the cell.
 2. The bipolarelectrochemical cell of claim 1, wherein the bipolar electrochemicalcell is a flow cell.
 3. The bipolar electrochemical cell of claim 1,wherein at least one of the first anode, the second anode, the firstcathode, and the second cathode includes the semi-solid ion-storingredox composition, the semi-solid ion-storing redox compositioncomprising a mixture of a liquid phase and a solid phase.
 4. The bipolarelectrochemical cell of claim 1, wherein at least one of the firstanode, the second anode, the first cathode, and the second cathodeincludes the semi-solid ion-storing redox composition, the semi-solidion-storing redox composition comprising a slurry.
 5. The bipolarelectrochemical cell of claim 1, wherein at least one of the firstanode, the second anode, the first cathode, and the second cathodeincludes the semi-solid ion-storing redox composition, the semi-solidion-storing redox composition comprising a particle suspension.
 6. Thebipolar electrochemical cell of claim 1, wherein at least one of thefirst anode, the second anode, the first cathode, and the second cathodeincludes the semi-solid ion-storing redox composition, the semi-solidion-storing redox composition comprising a colloidal suspension.
 7. Thebipolar electrochemical cell of claim 1, wherein at least one of thefirst anode, the second anode, the first cathode, and the second cathodeincludes the semi-solid ion-storing redox composition, the semi-solidion-storing redox composition comprising an emulsion.
 8. The bipolarelectrochemical cell of claim 1, wherein at least one of the firstanode, the second anode, the first cathode, and the second cathodeincludes the semi-solid ion-storing redox composition, the semi-solidion-storing redox composition comprising a micelle.
 9. The bipolarelectrochemical cell of claim 1, wherein the bipolar electrode includesan anode current collector, a cathode current collector, and a heat sinkdisposed between the anode current collector and the cathode currentcollector.
 10. bipolar electrochemical cell of claim 1, wherein thebipolar electrode includes an anode current collector, a cathode currentcollector, and an insulator disposed between the anode current collectorand the cathode current collector.
 11. The bipolar electrochemical cellof claim 3, wherein the liquid phase includes a non-aqueous liquidelectrolyte.
 12. A bipolar electrochemical cell, comprising: a terminalanode current collector; a first ion-permeable membrane spaced from theterminal anode current collector and at least partially defining a firstanode; a bipolar electrode spaced from the first ion-permeable membraneand at least partially defining a first cathode between the firstion-permeable membrane and a first surface of the bipolar currentcollector; a second ion-permeable membrane spaced from the bipolarcurrent collector and at least partially defining a second anode betweenthe second ion-permeable membrane and a second surface of the bipolarcurrent collector; and a terminal cathode current collector spaced fromthe second ion-permeable membrane and at least partially defining asecond cathode between the terminal cathode current collector and thesecond ion-permeable membrane, wherein at least one of the first anode,the second anode, the first cathode, and the second cathode includes asemi-solid electrode, the semi-solid electrode including a suspension ofan ion-storing solid phase material and a conductive additive in anon-aqueous liquid electrolyte, and wherein the volume percentage of theion-storing solid phase material is between 20% and 70%.
 13. The bipolarelectrochemical cell of claim 12, wherein the bipolar electrochemicalcell is a flow cell.
 14. The bipolar electrochemical cell of claim 12,wherein the suspension is a particle suspension.
 15. The bipolarelectrochemical cell of claim 12, wherein the bipolar electrode includesan anode current collector, a cathode current collector, and a heat sinkdisposed between the anode current collector and the cathode currentcollector.
 16. The bipolar electrochemical cell of claim 12, wherein thebipolar electrode includes an anode current collector, a cathode currentcollector, and an insulator disposed between the anode current collectorand the cathode current collector.
 17. A bipolar electrochemical cell,comprising: a terminal anode, a terminal cathode, and at least onebipolar electrode disposed between the terminal anode and the terminalcathode, the bipolar electrode including an anode portion, and a cathodeportion opposite the anode portion; a first ion-permeable membranedisposed between the terminal anode and the cathode portion of thebipolar electrode; and a second ion-permeable membrane disposed betweenthe terminal cathode and the anode portion of the bipolar electrode,wherein at least one of the terminal anode, the terminal cathode and theat least one bipolar electrode includes a semi-solid electrode, thesemi-solid electrode including a suspension of an ion-storing solidphase material and a conductive additive in a non-aqueous liquidelectrolyte, and wherein the volume percentage of the ion-storing solidphase material is between 20% and 70%.
 18. The bipolar electrochemicalcell of claim 17, wherein the bipolar electrochemical cell is a flowcell.
 19. The bipolar electrochemical cell of claim 17, wherein thesuspension is a particle suspension.
 20. The bipolar electrochemicalcell of claim 17, wherein the bipolar electrode includes an anodecurrent collector and a cathode current collector.
 21. The bipolarelectrochemical cell of claim 20, wherein the bipolar electrode furtherincludes a heat sink disposed between the anode current collector andthe cathode current collector.
 22. The bipolar electrochemical cell ofclaim 20, wherein the bipolar electrode further includes an insulatordisposed between the anode current collector and the cathode currentcollector.